Patent GB-161752-A (GB)
Title: A new method of obtaining the artillery data for firing at a rapidly moving object, and apparatus therefor
IPC: F41G5/08
Filed: 1920-02-04
Abstract: 161,752. Bruine, F. H. de. Feb. 4, 1920. Sights and methods of sighting. -Consists in sighting-apparatus, for use especially against aerial targets, having means for determining the angles of lead due to the speed of the target, the range or tangent angle of elevation and fuze time corrected for the angle of sight, and the velocity of the target,. The essential feature of the apparatus is a guide-plane, controlling the movements of the sight, which can be adjusted to coincide with the plane of flight, i.e. the plane containing the line of flight of the target and the line of sight. In the apparatus shown, this plane is defined by a disc 23 mounted in gymbal-like bearings, so that it can be set in the required direction by means of two toothed segments 18, 19. The telescope is mounted to move parallel to the guide-disc, on a pivot 53 on a block 38 which can be adjusted radially on a disc 36 adapted to rotate about a central axis 31 perpendicular to the guide-disc 23. An arm 52 projects laterally from the sight base 41 and slides and rotates in a bearing 47 on an adjustable block 46 mounted on an arm 45 projecting from an intermediate rotating disk 32, these two arms together with the perpendicular distance between the pivots 31, 53 forming a linkage by which the angle of lead is determined. In use, the block 38 is adjusted radially in accordance with the speed of the target, and the block 46 is adjusted along the bar 45 in accordance with the range and time of flight; the telescope is primarily rotated to follow the target by rotating the disc 32 about the pivot 31 by operating the arm 45, the dotted line 53, 42, Fig. 3, then representing the line of sight; the disc 36 is then rotated about the axis 31 relatively to the disc 32 until the common perpendicular of the pivots 31, 53 lies along the radius of greatest inclination of the guide disc, as shown at 31, 53<1>, Fig. 3; the axial line of the telescope is thereby rotated through an angle a to the position 53<1>, 42<1>, Fig. 3, this angle a being the angle of lead in the plane of flight. The angle of sight is indicated by a pointer 11 on a plate 9, the pointer being carried by an arm 13 which moves parallel to the line of sight. One side of the plate 9 is marked with range or tangent elevation curves and the other with fuze times and the pointer is forked so as to engage both sides. The speed of the target can be determined by setting up in the apparatus a triangle representing the line of sight, line of flight of the target, and the perpendicular from the observing point on to the line of flight. This triangle is represented in Fig. 3 by the graduated bars 29, 40, 50, of which the bar 29 is carried by a disc 26, Fig. 1, and is parallel to the line of sight, the bar 50 is carried by the block 38, Fig. 2, and is a continuation of the line 31, 53<1>, and the bar 40 is carried by a sleeve 51 sliding on the bar 50. The range at the commencement of the observation being known, the movement of the target along the bar 40 in a known time enables its speed to be determined.